Ruins of Kilwa Kisiwani and Songo Mnara (C/1981) On two small islands near the coast, the remains of two great East African ports admired by early European explorers can be found. From the 13th to the 16th centuries, the merchants of Kilwa traded gold, silver, pearls, perfumes, Arabian crockery, Persian earthenware and Chinese porcelain, much of the trade in the Indian Ocean thus passing through their hands.